![Uwe Kleine-König](/assets/img/avatar_default.png)
This patch allows to trace gpio operations using ftrace Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
1740 lines
42 KiB
C
1740 lines
42 KiB
C
#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/debugfs.h>
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#include <linux/seq_file.h>
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#include <linux/gpio.h>
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#include <linux/of_gpio.h>
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#include <linux/idr.h>
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#include <linux/slab.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/gpio.h>
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/* Optional implementation infrastructure for GPIO interfaces.
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*
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* Platforms may want to use this if they tend to use very many GPIOs
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* that aren't part of a System-On-Chip core; or across I2C/SPI/etc.
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*
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* When kernel footprint or instruction count is an issue, simpler
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* implementations may be preferred. The GPIO programming interface
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* allows for inlining speed-critical get/set operations for common
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* cases, so that access to SOC-integrated GPIOs can sometimes cost
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* only an instruction or two per bit.
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*/
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/* When debugging, extend minimal trust to callers and platform code.
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* Also emit diagnostic messages that may help initial bringup, when
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* board setup or driver bugs are most common.
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*
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* Otherwise, minimize overhead in what may be bitbanging codepaths.
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*/
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#ifdef DEBUG
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#define extra_checks 1
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#else
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#define extra_checks 0
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#endif
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/* gpio_lock prevents conflicts during gpio_desc[] table updates.
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* While any GPIO is requested, its gpio_chip is not removable;
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* each GPIO's "requested" flag serves as a lock and refcount.
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*/
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static DEFINE_SPINLOCK(gpio_lock);
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struct gpio_desc {
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struct gpio_chip *chip;
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unsigned long flags;
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/* flag symbols are bit numbers */
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#define FLAG_REQUESTED 0
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#define FLAG_IS_OUT 1
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#define FLAG_RESERVED 2
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#define FLAG_EXPORT 3 /* protected by sysfs_lock */
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#define FLAG_SYSFS 4 /* exported via /sys/class/gpio/control */
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#define FLAG_TRIG_FALL 5 /* trigger on falling edge */
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#define FLAG_TRIG_RISE 6 /* trigger on rising edge */
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#define FLAG_ACTIVE_LOW 7 /* sysfs value has active low */
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#define ID_SHIFT 16 /* add new flags before this one */
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#define GPIO_FLAGS_MASK ((1 << ID_SHIFT) - 1)
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#define GPIO_TRIGGER_MASK (BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))
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#ifdef CONFIG_DEBUG_FS
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const char *label;
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#endif
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};
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static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];
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#ifdef CONFIG_GPIO_SYSFS
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static DEFINE_IDR(dirent_idr);
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#endif
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static inline void desc_set_label(struct gpio_desc *d, const char *label)
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{
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#ifdef CONFIG_DEBUG_FS
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d->label = label;
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#endif
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}
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/* Warn when drivers omit gpio_request() calls -- legal but ill-advised
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* when setting direction, and otherwise illegal. Until board setup code
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* and drivers use explicit requests everywhere (which won't happen when
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* those calls have no teeth) we can't avoid autorequesting. This nag
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* message should motivate switching to explicit requests... so should
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* the weaker cleanup after faults, compared to gpio_request().
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*
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* NOTE: the autorequest mechanism is going away; at this point it's
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* only "legal" in the sense that (old) code using it won't break yet,
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* but instead only triggers a WARN() stack dump.
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*/
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static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
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{
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const struct gpio_chip *chip = desc->chip;
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const int gpio = chip->base + offset;
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if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
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"autorequest GPIO-%d\n", gpio)) {
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if (!try_module_get(chip->owner)) {
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pr_err("GPIO-%d: module can't be gotten \n", gpio);
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clear_bit(FLAG_REQUESTED, &desc->flags);
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/* lose */
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return -EIO;
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}
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desc_set_label(desc, "[auto]");
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/* caller must chip->request() w/o spinlock */
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if (chip->request)
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return 1;
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}
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return 0;
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}
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/* caller holds gpio_lock *OR* gpio is marked as requested */
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static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
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{
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return gpio_desc[gpio].chip;
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}
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/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
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static int gpiochip_find_base(int ngpio)
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{
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int i;
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int spare = 0;
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int base = -ENOSPC;
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for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
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struct gpio_desc *desc = &gpio_desc[i];
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struct gpio_chip *chip = desc->chip;
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if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) {
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spare++;
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if (spare == ngpio) {
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base = i;
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break;
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}
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} else {
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spare = 0;
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if (chip)
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i -= chip->ngpio - 1;
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}
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}
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if (gpio_is_valid(base))
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pr_debug("%s: found new base at %d\n", __func__, base);
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return base;
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}
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/**
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* gpiochip_reserve() - reserve range of gpios to use with platform code only
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* @start: starting gpio number
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* @ngpio: number of gpios to reserve
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* Context: platform init, potentially before irqs or kmalloc will work
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*
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* Returns a negative errno if any gpio within the range is already reserved
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* or registered, else returns zero as a success code. Use this function
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* to mark a range of gpios as unavailable for dynamic gpio number allocation,
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* for example because its driver support is not yet loaded.
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*/
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int __init gpiochip_reserve(int start, int ngpio)
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{
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int ret = 0;
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unsigned long flags;
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int i;
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if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1))
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return -EINVAL;
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spin_lock_irqsave(&gpio_lock, flags);
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for (i = start; i < start + ngpio; i++) {
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struct gpio_desc *desc = &gpio_desc[i];
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if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) {
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ret = -EBUSY;
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goto err;
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}
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set_bit(FLAG_RESERVED, &desc->flags);
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}
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pr_debug("%s: reserved gpios from %d to %d\n",
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__func__, start, start + ngpio - 1);
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err:
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spin_unlock_irqrestore(&gpio_lock, flags);
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return ret;
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}
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#ifdef CONFIG_GPIO_SYSFS
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/* lock protects against unexport_gpio() being called while
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* sysfs files are active.
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*/
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static DEFINE_MUTEX(sysfs_lock);
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/*
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* /sys/class/gpio/gpioN... only for GPIOs that are exported
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* /direction
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* * MAY BE OMITTED if kernel won't allow direction changes
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* * is read/write as "in" or "out"
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* * may also be written as "high" or "low", initializing
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* output value as specified ("out" implies "low")
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* /value
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* * always readable, subject to hardware behavior
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* * may be writable, as zero/nonzero
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* /edge
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* * configures behavior of poll(2) on /value
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* * available only if pin can generate IRQs on input
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* * is read/write as "none", "falling", "rising", or "both"
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* /active_low
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* * configures polarity of /value
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* * is read/write as zero/nonzero
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* * also affects existing and subsequent "falling" and "rising"
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* /edge configuration
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*/
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static ssize_t gpio_direction_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else
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status = sprintf(buf, "%s\n",
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test_bit(FLAG_IS_OUT, &desc->flags)
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? "out" : "in");
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_direction_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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unsigned gpio = desc - gpio_desc;
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else if (sysfs_streq(buf, "high"))
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status = gpio_direction_output(gpio, 1);
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else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
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status = gpio_direction_output(gpio, 0);
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else if (sysfs_streq(buf, "in"))
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status = gpio_direction_input(gpio);
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else
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status = -EINVAL;
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mutex_unlock(&sysfs_lock);
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return status ? : size;
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}
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static /* const */ DEVICE_ATTR(direction, 0644,
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gpio_direction_show, gpio_direction_store);
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static ssize_t gpio_value_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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unsigned gpio = desc - gpio_desc;
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags)) {
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status = -EIO;
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} else {
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int value;
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value = !!gpio_get_value_cansleep(gpio);
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if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
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value = !value;
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status = sprintf(buf, "%d\n", value);
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_value_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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unsigned gpio = desc - gpio_desc;
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else if (!test_bit(FLAG_IS_OUT, &desc->flags))
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status = -EPERM;
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else {
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long value;
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status = strict_strtol(buf, 0, &value);
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if (status == 0) {
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if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
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value = !value;
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gpio_set_value_cansleep(gpio, value != 0);
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status = size;
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}
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static const DEVICE_ATTR(value, 0644,
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gpio_value_show, gpio_value_store);
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static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
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{
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struct sysfs_dirent *value_sd = priv;
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sysfs_notify_dirent(value_sd);
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return IRQ_HANDLED;
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}
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static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
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unsigned long gpio_flags)
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{
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struct sysfs_dirent *value_sd;
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unsigned long irq_flags;
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int ret, irq, id;
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if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
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return 0;
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irq = gpio_to_irq(desc - gpio_desc);
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if (irq < 0)
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return -EIO;
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id = desc->flags >> ID_SHIFT;
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value_sd = idr_find(&dirent_idr, id);
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if (value_sd)
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free_irq(irq, value_sd);
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desc->flags &= ~GPIO_TRIGGER_MASK;
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if (!gpio_flags) {
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ret = 0;
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goto free_id;
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}
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irq_flags = IRQF_SHARED;
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if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
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irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
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IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
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if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
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irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
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IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
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if (!value_sd) {
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value_sd = sysfs_get_dirent(dev->kobj.sd, NULL, "value");
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if (!value_sd) {
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ret = -ENODEV;
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goto err_out;
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}
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do {
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ret = -ENOMEM;
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if (idr_pre_get(&dirent_idr, GFP_KERNEL))
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ret = idr_get_new_above(&dirent_idr, value_sd,
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1, &id);
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} while (ret == -EAGAIN);
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if (ret)
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goto free_sd;
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desc->flags &= GPIO_FLAGS_MASK;
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desc->flags |= (unsigned long)id << ID_SHIFT;
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if (desc->flags >> ID_SHIFT != id) {
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ret = -ERANGE;
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goto free_id;
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}
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}
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ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
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"gpiolib", value_sd);
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if (ret < 0)
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goto free_id;
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desc->flags |= gpio_flags;
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return 0;
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free_id:
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idr_remove(&dirent_idr, id);
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desc->flags &= GPIO_FLAGS_MASK;
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free_sd:
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if (value_sd)
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sysfs_put(value_sd);
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err_out:
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return ret;
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}
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static const struct {
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const char *name;
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unsigned long flags;
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} trigger_types[] = {
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{ "none", 0 },
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{ "falling", BIT(FLAG_TRIG_FALL) },
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{ "rising", BIT(FLAG_TRIG_RISE) },
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{ "both", BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
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};
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static ssize_t gpio_edge_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else {
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int i;
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status = 0;
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for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
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if ((desc->flags & GPIO_TRIGGER_MASK)
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== trigger_types[i].flags) {
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status = sprintf(buf, "%s\n",
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trigger_types[i].name);
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break;
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}
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static ssize_t gpio_edge_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
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{
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struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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int i;
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for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
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if (sysfs_streq(trigger_types[i].name, buf))
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goto found;
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return -EINVAL;
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found:
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else {
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status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
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if (!status)
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status = size;
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}
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mutex_unlock(&sysfs_lock);
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return status;
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}
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static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);
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static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
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int value)
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{
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int status = 0;
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if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
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return 0;
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if (value)
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set_bit(FLAG_ACTIVE_LOW, &desc->flags);
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else
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clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
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/* reconfigure poll(2) support if enabled on one edge only */
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if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
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!!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
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unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;
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gpio_setup_irq(desc, dev, 0);
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status = gpio_setup_irq(desc, dev, trigger_flags);
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}
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return status;
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}
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|
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static ssize_t gpio_active_low_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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const struct gpio_desc *desc = dev_get_drvdata(dev);
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ssize_t status;
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|
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mutex_lock(&sysfs_lock);
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if (!test_bit(FLAG_EXPORT, &desc->flags))
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status = -EIO;
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else
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status = sprintf(buf, "%d\n",
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!!test_bit(FLAG_ACTIVE_LOW, &desc->flags));
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mutex_unlock(&sysfs_lock);
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return status;
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}
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|
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static ssize_t gpio_active_low_store(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t size)
|
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{
|
|
struct gpio_desc *desc = dev_get_drvdata(dev);
|
|
ssize_t status;
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
if (!test_bit(FLAG_EXPORT, &desc->flags)) {
|
|
status = -EIO;
|
|
} else {
|
|
long value;
|
|
|
|
status = strict_strtol(buf, 0, &value);
|
|
if (status == 0)
|
|
status = sysfs_set_active_low(desc, dev, value != 0);
|
|
}
|
|
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
return status ? : size;
|
|
}
|
|
|
|
static const DEVICE_ATTR(active_low, 0644,
|
|
gpio_active_low_show, gpio_active_low_store);
|
|
|
|
static const struct attribute *gpio_attrs[] = {
|
|
&dev_attr_value.attr,
|
|
&dev_attr_active_low.attr,
|
|
NULL,
|
|
};
|
|
|
|
static const struct attribute_group gpio_attr_group = {
|
|
.attrs = (struct attribute **) gpio_attrs,
|
|
};
|
|
|
|
/*
|
|
* /sys/class/gpio/gpiochipN/
|
|
* /base ... matching gpio_chip.base (N)
|
|
* /label ... matching gpio_chip.label
|
|
* /ngpio ... matching gpio_chip.ngpio
|
|
*/
|
|
|
|
static ssize_t chip_base_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
const struct gpio_chip *chip = dev_get_drvdata(dev);
|
|
|
|
return sprintf(buf, "%d\n", chip->base);
|
|
}
|
|
static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
|
|
|
|
static ssize_t chip_label_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
const struct gpio_chip *chip = dev_get_drvdata(dev);
|
|
|
|
return sprintf(buf, "%s\n", chip->label ? : "");
|
|
}
|
|
static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
|
|
|
|
static ssize_t chip_ngpio_show(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
const struct gpio_chip *chip = dev_get_drvdata(dev);
|
|
|
|
return sprintf(buf, "%u\n", chip->ngpio);
|
|
}
|
|
static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
|
|
|
|
static const struct attribute *gpiochip_attrs[] = {
|
|
&dev_attr_base.attr,
|
|
&dev_attr_label.attr,
|
|
&dev_attr_ngpio.attr,
|
|
NULL,
|
|
};
|
|
|
|
static const struct attribute_group gpiochip_attr_group = {
|
|
.attrs = (struct attribute **) gpiochip_attrs,
|
|
};
|
|
|
|
/*
|
|
* /sys/class/gpio/export ... write-only
|
|
* integer N ... number of GPIO to export (full access)
|
|
* /sys/class/gpio/unexport ... write-only
|
|
* integer N ... number of GPIO to unexport
|
|
*/
|
|
static ssize_t export_store(struct class *class,
|
|
struct class_attribute *attr,
|
|
const char *buf, size_t len)
|
|
{
|
|
long gpio;
|
|
int status;
|
|
|
|
status = strict_strtol(buf, 0, &gpio);
|
|
if (status < 0)
|
|
goto done;
|
|
|
|
/* No extra locking here; FLAG_SYSFS just signifies that the
|
|
* request and export were done by on behalf of userspace, so
|
|
* they may be undone on its behalf too.
|
|
*/
|
|
|
|
status = gpio_request(gpio, "sysfs");
|
|
if (status < 0)
|
|
goto done;
|
|
|
|
status = gpio_export(gpio, true);
|
|
if (status < 0)
|
|
gpio_free(gpio);
|
|
else
|
|
set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags);
|
|
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: status %d\n", __func__, status);
|
|
return status ? : len;
|
|
}
|
|
|
|
static ssize_t unexport_store(struct class *class,
|
|
struct class_attribute *attr,
|
|
const char *buf, size_t len)
|
|
{
|
|
long gpio;
|
|
int status;
|
|
|
|
status = strict_strtol(buf, 0, &gpio);
|
|
if (status < 0)
|
|
goto done;
|
|
|
|
status = -EINVAL;
|
|
|
|
/* reject bogus commands (gpio_unexport ignores them) */
|
|
if (!gpio_is_valid(gpio))
|
|
goto done;
|
|
|
|
/* No extra locking here; FLAG_SYSFS just signifies that the
|
|
* request and export were done by on behalf of userspace, so
|
|
* they may be undone on its behalf too.
|
|
*/
|
|
if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) {
|
|
status = 0;
|
|
gpio_free(gpio);
|
|
}
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: status %d\n", __func__, status);
|
|
return status ? : len;
|
|
}
|
|
|
|
static struct class_attribute gpio_class_attrs[] = {
|
|
__ATTR(export, 0200, NULL, export_store),
|
|
__ATTR(unexport, 0200, NULL, unexport_store),
|
|
__ATTR_NULL,
|
|
};
|
|
|
|
static struct class gpio_class = {
|
|
.name = "gpio",
|
|
.owner = THIS_MODULE,
|
|
|
|
.class_attrs = gpio_class_attrs,
|
|
};
|
|
|
|
|
|
/**
|
|
* gpio_export - export a GPIO through sysfs
|
|
* @gpio: gpio to make available, already requested
|
|
* @direction_may_change: true if userspace may change gpio direction
|
|
* Context: arch_initcall or later
|
|
*
|
|
* When drivers want to make a GPIO accessible to userspace after they
|
|
* have requested it -- perhaps while debugging, or as part of their
|
|
* public interface -- they may use this routine. If the GPIO can
|
|
* change direction (some can't) and the caller allows it, userspace
|
|
* will see "direction" sysfs attribute which may be used to change
|
|
* the gpio's direction. A "value" attribute will always be provided.
|
|
*
|
|
* Returns zero on success, else an error.
|
|
*/
|
|
int gpio_export(unsigned gpio, bool direction_may_change)
|
|
{
|
|
unsigned long flags;
|
|
struct gpio_desc *desc;
|
|
int status = -EINVAL;
|
|
const char *ioname = NULL;
|
|
|
|
/* can't export until sysfs is available ... */
|
|
if (!gpio_class.p) {
|
|
pr_debug("%s: called too early!\n", __func__);
|
|
return -ENOENT;
|
|
}
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto done;
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
desc = &gpio_desc[gpio];
|
|
if (test_bit(FLAG_REQUESTED, &desc->flags)
|
|
&& !test_bit(FLAG_EXPORT, &desc->flags)) {
|
|
status = 0;
|
|
if (!desc->chip->direction_input
|
|
|| !desc->chip->direction_output)
|
|
direction_may_change = false;
|
|
}
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
if (desc->chip->names && desc->chip->names[gpio - desc->chip->base])
|
|
ioname = desc->chip->names[gpio - desc->chip->base];
|
|
|
|
if (status == 0) {
|
|
struct device *dev;
|
|
|
|
dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
|
|
desc, ioname ? ioname : "gpio%u", gpio);
|
|
if (!IS_ERR(dev)) {
|
|
status = sysfs_create_group(&dev->kobj,
|
|
&gpio_attr_group);
|
|
|
|
if (!status && direction_may_change)
|
|
status = device_create_file(dev,
|
|
&dev_attr_direction);
|
|
|
|
if (!status && gpio_to_irq(gpio) >= 0
|
|
&& (direction_may_change
|
|
|| !test_bit(FLAG_IS_OUT,
|
|
&desc->flags)))
|
|
status = device_create_file(dev,
|
|
&dev_attr_edge);
|
|
|
|
if (status != 0)
|
|
device_unregister(dev);
|
|
} else
|
|
status = PTR_ERR(dev);
|
|
if (status == 0)
|
|
set_bit(FLAG_EXPORT, &desc->flags);
|
|
}
|
|
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_export);
|
|
|
|
static int match_export(struct device *dev, void *data)
|
|
{
|
|
return dev_get_drvdata(dev) == data;
|
|
}
|
|
|
|
/**
|
|
* gpio_export_link - create a sysfs link to an exported GPIO node
|
|
* @dev: device under which to create symlink
|
|
* @name: name of the symlink
|
|
* @gpio: gpio to create symlink to, already exported
|
|
*
|
|
* Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
|
|
* node. Caller is responsible for unlinking.
|
|
*
|
|
* Returns zero on success, else an error.
|
|
*/
|
|
int gpio_export_link(struct device *dev, const char *name, unsigned gpio)
|
|
{
|
|
struct gpio_desc *desc;
|
|
int status = -EINVAL;
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto done;
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
desc = &gpio_desc[gpio];
|
|
|
|
if (test_bit(FLAG_EXPORT, &desc->flags)) {
|
|
struct device *tdev;
|
|
|
|
tdev = class_find_device(&gpio_class, NULL, desc, match_export);
|
|
if (tdev != NULL) {
|
|
status = sysfs_create_link(&dev->kobj, &tdev->kobj,
|
|
name);
|
|
} else {
|
|
status = -ENODEV;
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_export_link);
|
|
|
|
|
|
/**
|
|
* gpio_sysfs_set_active_low - set the polarity of gpio sysfs value
|
|
* @gpio: gpio to change
|
|
* @value: non-zero to use active low, i.e. inverted values
|
|
*
|
|
* Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
|
|
* The GPIO does not have to be exported yet. If poll(2) support has
|
|
* been enabled for either rising or falling edge, it will be
|
|
* reconfigured to follow the new polarity.
|
|
*
|
|
* Returns zero on success, else an error.
|
|
*/
|
|
int gpio_sysfs_set_active_low(unsigned gpio, int value)
|
|
{
|
|
struct gpio_desc *desc;
|
|
struct device *dev = NULL;
|
|
int status = -EINVAL;
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto done;
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
desc = &gpio_desc[gpio];
|
|
|
|
if (test_bit(FLAG_EXPORT, &desc->flags)) {
|
|
dev = class_find_device(&gpio_class, NULL, desc, match_export);
|
|
if (dev == NULL) {
|
|
status = -ENODEV;
|
|
goto unlock;
|
|
}
|
|
}
|
|
|
|
status = sysfs_set_active_low(desc, dev, value);
|
|
|
|
unlock:
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_sysfs_set_active_low);
|
|
|
|
/**
|
|
* gpio_unexport - reverse effect of gpio_export()
|
|
* @gpio: gpio to make unavailable
|
|
*
|
|
* This is implicit on gpio_free().
|
|
*/
|
|
void gpio_unexport(unsigned gpio)
|
|
{
|
|
struct gpio_desc *desc;
|
|
int status = 0;
|
|
|
|
if (!gpio_is_valid(gpio)) {
|
|
status = -EINVAL;
|
|
goto done;
|
|
}
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
|
|
desc = &gpio_desc[gpio];
|
|
|
|
if (test_bit(FLAG_EXPORT, &desc->flags)) {
|
|
struct device *dev = NULL;
|
|
|
|
dev = class_find_device(&gpio_class, NULL, desc, match_export);
|
|
if (dev) {
|
|
gpio_setup_irq(desc, dev, 0);
|
|
clear_bit(FLAG_EXPORT, &desc->flags);
|
|
put_device(dev);
|
|
device_unregister(dev);
|
|
} else
|
|
status = -ENODEV;
|
|
}
|
|
|
|
mutex_unlock(&sysfs_lock);
|
|
done:
|
|
if (status)
|
|
pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_unexport);
|
|
|
|
static int gpiochip_export(struct gpio_chip *chip)
|
|
{
|
|
int status;
|
|
struct device *dev;
|
|
|
|
/* Many systems register gpio chips for SOC support very early,
|
|
* before driver model support is available. In those cases we
|
|
* export this later, in gpiolib_sysfs_init() ... here we just
|
|
* verify that _some_ field of gpio_class got initialized.
|
|
*/
|
|
if (!gpio_class.p)
|
|
return 0;
|
|
|
|
/* use chip->base for the ID; it's already known to be unique */
|
|
mutex_lock(&sysfs_lock);
|
|
dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
|
|
"gpiochip%d", chip->base);
|
|
if (!IS_ERR(dev)) {
|
|
status = sysfs_create_group(&dev->kobj,
|
|
&gpiochip_attr_group);
|
|
} else
|
|
status = PTR_ERR(dev);
|
|
chip->exported = (status == 0);
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
if (status) {
|
|
unsigned long flags;
|
|
unsigned gpio;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
gpio = chip->base;
|
|
while (gpio_desc[gpio].chip == chip)
|
|
gpio_desc[gpio++].chip = NULL;
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
pr_debug("%s: chip %s status %d\n", __func__,
|
|
chip->label, status);
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
static void gpiochip_unexport(struct gpio_chip *chip)
|
|
{
|
|
int status;
|
|
struct device *dev;
|
|
|
|
mutex_lock(&sysfs_lock);
|
|
dev = class_find_device(&gpio_class, NULL, chip, match_export);
|
|
if (dev) {
|
|
put_device(dev);
|
|
device_unregister(dev);
|
|
chip->exported = 0;
|
|
status = 0;
|
|
} else
|
|
status = -ENODEV;
|
|
mutex_unlock(&sysfs_lock);
|
|
|
|
if (status)
|
|
pr_debug("%s: chip %s status %d\n", __func__,
|
|
chip->label, status);
|
|
}
|
|
|
|
static int __init gpiolib_sysfs_init(void)
|
|
{
|
|
int status;
|
|
unsigned long flags;
|
|
unsigned gpio;
|
|
|
|
status = class_register(&gpio_class);
|
|
if (status < 0)
|
|
return status;
|
|
|
|
/* Scan and register the gpio_chips which registered very
|
|
* early (e.g. before the class_register above was called).
|
|
*
|
|
* We run before arch_initcall() so chip->dev nodes can have
|
|
* registered, and so arch_initcall() can always gpio_export().
|
|
*/
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
|
|
struct gpio_chip *chip;
|
|
|
|
chip = gpio_desc[gpio].chip;
|
|
if (!chip || chip->exported)
|
|
continue;
|
|
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
status = gpiochip_export(chip);
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
}
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
|
|
return status;
|
|
}
|
|
postcore_initcall(gpiolib_sysfs_init);
|
|
|
|
#else
|
|
static inline int gpiochip_export(struct gpio_chip *chip)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void gpiochip_unexport(struct gpio_chip *chip)
|
|
{
|
|
}
|
|
|
|
#endif /* CONFIG_GPIO_SYSFS */
|
|
|
|
/**
|
|
* gpiochip_add() - register a gpio_chip
|
|
* @chip: the chip to register, with chip->base initialized
|
|
* Context: potentially before irqs or kmalloc will work
|
|
*
|
|
* Returns a negative errno if the chip can't be registered, such as
|
|
* because the chip->base is invalid or already associated with a
|
|
* different chip. Otherwise it returns zero as a success code.
|
|
*
|
|
* When gpiochip_add() is called very early during boot, so that GPIOs
|
|
* can be freely used, the chip->dev device must be registered before
|
|
* the gpio framework's arch_initcall(). Otherwise sysfs initialization
|
|
* for GPIOs will fail rudely.
|
|
*
|
|
* If chip->base is negative, this requests dynamic assignment of
|
|
* a range of valid GPIOs.
|
|
*/
|
|
int gpiochip_add(struct gpio_chip *chip)
|
|
{
|
|
unsigned long flags;
|
|
int status = 0;
|
|
unsigned id;
|
|
int base = chip->base;
|
|
|
|
if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
|
|
&& base >= 0) {
|
|
status = -EINVAL;
|
|
goto fail;
|
|
}
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
if (base < 0) {
|
|
base = gpiochip_find_base(chip->ngpio);
|
|
if (base < 0) {
|
|
status = base;
|
|
goto unlock;
|
|
}
|
|
chip->base = base;
|
|
}
|
|
|
|
/* these GPIO numbers must not be managed by another gpio_chip */
|
|
for (id = base; id < base + chip->ngpio; id++) {
|
|
if (gpio_desc[id].chip != NULL) {
|
|
status = -EBUSY;
|
|
break;
|
|
}
|
|
}
|
|
if (status == 0) {
|
|
for (id = base; id < base + chip->ngpio; id++) {
|
|
gpio_desc[id].chip = chip;
|
|
|
|
/* REVISIT: most hardware initializes GPIOs as
|
|
* inputs (often with pullups enabled) so power
|
|
* usage is minimized. Linux code should set the
|
|
* gpio direction first thing; but until it does,
|
|
* we may expose the wrong direction in sysfs.
|
|
*/
|
|
gpio_desc[id].flags = !chip->direction_input
|
|
? (1 << FLAG_IS_OUT)
|
|
: 0;
|
|
}
|
|
}
|
|
|
|
of_gpiochip_add(chip);
|
|
|
|
unlock:
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
if (status)
|
|
goto fail;
|
|
|
|
status = gpiochip_export(chip);
|
|
if (status)
|
|
goto fail;
|
|
|
|
return 0;
|
|
fail:
|
|
/* failures here can mean systems won't boot... */
|
|
pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
|
|
chip->base, chip->base + chip->ngpio - 1,
|
|
chip->label ? : "generic");
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiochip_add);
|
|
|
|
/**
|
|
* gpiochip_remove() - unregister a gpio_chip
|
|
* @chip: the chip to unregister
|
|
*
|
|
* A gpio_chip with any GPIOs still requested may not be removed.
|
|
*/
|
|
int gpiochip_remove(struct gpio_chip *chip)
|
|
{
|
|
unsigned long flags;
|
|
int status = 0;
|
|
unsigned id;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
of_gpiochip_remove(chip);
|
|
|
|
for (id = chip->base; id < chip->base + chip->ngpio; id++) {
|
|
if (test_bit(FLAG_REQUESTED, &gpio_desc[id].flags)) {
|
|
status = -EBUSY;
|
|
break;
|
|
}
|
|
}
|
|
if (status == 0) {
|
|
for (id = chip->base; id < chip->base + chip->ngpio; id++)
|
|
gpio_desc[id].chip = NULL;
|
|
}
|
|
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
if (status == 0)
|
|
gpiochip_unexport(chip);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiochip_remove);
|
|
|
|
/**
|
|
* gpiochip_find() - iterator for locating a specific gpio_chip
|
|
* @data: data to pass to match function
|
|
* @callback: Callback function to check gpio_chip
|
|
*
|
|
* Similar to bus_find_device. It returns a reference to a gpio_chip as
|
|
* determined by a user supplied @match callback. The callback should return
|
|
* 0 if the device doesn't match and non-zero if it does. If the callback is
|
|
* non-zero, this function will return to the caller and not iterate over any
|
|
* more gpio_chips.
|
|
*/
|
|
struct gpio_chip *gpiochip_find(void *data,
|
|
int (*match)(struct gpio_chip *chip, void *data))
|
|
{
|
|
struct gpio_chip *chip = NULL;
|
|
unsigned long flags;
|
|
int i;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
for (i = 0; i < ARCH_NR_GPIOS; i++) {
|
|
if (!gpio_desc[i].chip)
|
|
continue;
|
|
|
|
if (match(gpio_desc[i].chip, data)) {
|
|
chip = gpio_desc[i].chip;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
return chip;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiochip_find);
|
|
|
|
/* These "optional" allocation calls help prevent drivers from stomping
|
|
* on each other, and help provide better diagnostics in debugfs.
|
|
* They're called even less than the "set direction" calls.
|
|
*/
|
|
int gpio_request(unsigned gpio, const char *label)
|
|
{
|
|
struct gpio_desc *desc;
|
|
struct gpio_chip *chip;
|
|
int status = -EINVAL;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto done;
|
|
desc = &gpio_desc[gpio];
|
|
chip = desc->chip;
|
|
if (chip == NULL)
|
|
goto done;
|
|
|
|
if (!try_module_get(chip->owner))
|
|
goto done;
|
|
|
|
/* NOTE: gpio_request() can be called in early boot,
|
|
* before IRQs are enabled, for non-sleeping (SOC) GPIOs.
|
|
*/
|
|
|
|
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
|
|
desc_set_label(desc, label ? : "?");
|
|
status = 0;
|
|
} else {
|
|
status = -EBUSY;
|
|
module_put(chip->owner);
|
|
goto done;
|
|
}
|
|
|
|
if (chip->request) {
|
|
/* chip->request may sleep */
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
status = chip->request(chip, gpio - chip->base);
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
if (status < 0) {
|
|
desc_set_label(desc, NULL);
|
|
module_put(chip->owner);
|
|
clear_bit(FLAG_REQUESTED, &desc->flags);
|
|
}
|
|
}
|
|
|
|
done:
|
|
if (status)
|
|
pr_debug("gpio_request: gpio-%d (%s) status %d\n",
|
|
gpio, label ? : "?", status);
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_request);
|
|
|
|
void gpio_free(unsigned gpio)
|
|
{
|
|
unsigned long flags;
|
|
struct gpio_desc *desc;
|
|
struct gpio_chip *chip;
|
|
|
|
might_sleep();
|
|
|
|
if (!gpio_is_valid(gpio)) {
|
|
WARN_ON(extra_checks);
|
|
return;
|
|
}
|
|
|
|
gpio_unexport(gpio);
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
desc = &gpio_desc[gpio];
|
|
chip = desc->chip;
|
|
if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
|
|
if (chip->free) {
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
might_sleep_if(chip->can_sleep);
|
|
chip->free(chip, gpio - chip->base);
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
}
|
|
desc_set_label(desc, NULL);
|
|
module_put(desc->chip->owner);
|
|
clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
|
|
clear_bit(FLAG_REQUESTED, &desc->flags);
|
|
} else
|
|
WARN_ON(extra_checks);
|
|
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_free);
|
|
|
|
/**
|
|
* gpio_request_one - request a single GPIO with initial configuration
|
|
* @gpio: the GPIO number
|
|
* @flags: GPIO configuration as specified by GPIOF_*
|
|
* @label: a literal description string of this GPIO
|
|
*/
|
|
int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
|
|
{
|
|
int err;
|
|
|
|
err = gpio_request(gpio, label);
|
|
if (err)
|
|
return err;
|
|
|
|
if (flags & GPIOF_DIR_IN)
|
|
err = gpio_direction_input(gpio);
|
|
else
|
|
err = gpio_direction_output(gpio,
|
|
(flags & GPIOF_INIT_HIGH) ? 1 : 0);
|
|
|
|
if (err)
|
|
gpio_free(gpio);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_request_one);
|
|
|
|
/**
|
|
* gpio_request_array - request multiple GPIOs in a single call
|
|
* @array: array of the 'struct gpio'
|
|
* @num: how many GPIOs in the array
|
|
*/
|
|
int gpio_request_array(struct gpio *array, size_t num)
|
|
{
|
|
int i, err;
|
|
|
|
for (i = 0; i < num; i++, array++) {
|
|
err = gpio_request_one(array->gpio, array->flags, array->label);
|
|
if (err)
|
|
goto err_free;
|
|
}
|
|
return 0;
|
|
|
|
err_free:
|
|
while (i--)
|
|
gpio_free((--array)->gpio);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_request_array);
|
|
|
|
/**
|
|
* gpio_free_array - release multiple GPIOs in a single call
|
|
* @array: array of the 'struct gpio'
|
|
* @num: how many GPIOs in the array
|
|
*/
|
|
void gpio_free_array(struct gpio *array, size_t num)
|
|
{
|
|
while (num--)
|
|
gpio_free((array++)->gpio);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_free_array);
|
|
|
|
/**
|
|
* gpiochip_is_requested - return string iff signal was requested
|
|
* @chip: controller managing the signal
|
|
* @offset: of signal within controller's 0..(ngpio - 1) range
|
|
*
|
|
* Returns NULL if the GPIO is not currently requested, else a string.
|
|
* If debugfs support is enabled, the string returned is the label passed
|
|
* to gpio_request(); otherwise it is a meaningless constant.
|
|
*
|
|
* This function is for use by GPIO controller drivers. The label can
|
|
* help with diagnostics, and knowing that the signal is used as a GPIO
|
|
* can help avoid accidentally multiplexing it to another controller.
|
|
*/
|
|
const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
|
|
{
|
|
unsigned gpio = chip->base + offset;
|
|
|
|
if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
|
|
return NULL;
|
|
if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
|
|
return NULL;
|
|
#ifdef CONFIG_DEBUG_FS
|
|
return gpio_desc[gpio].label;
|
|
#else
|
|
return "?";
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpiochip_is_requested);
|
|
|
|
|
|
/* Drivers MUST set GPIO direction before making get/set calls. In
|
|
* some cases this is done in early boot, before IRQs are enabled.
|
|
*
|
|
* As a rule these aren't called more than once (except for drivers
|
|
* using the open-drain emulation idiom) so these are natural places
|
|
* to accumulate extra debugging checks. Note that we can't (yet)
|
|
* rely on gpio_request() having been called beforehand.
|
|
*/
|
|
|
|
int gpio_direction_input(unsigned gpio)
|
|
{
|
|
unsigned long flags;
|
|
struct gpio_chip *chip;
|
|
struct gpio_desc *desc = &gpio_desc[gpio];
|
|
int status = -EINVAL;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto fail;
|
|
chip = desc->chip;
|
|
if (!chip || !chip->get || !chip->direction_input)
|
|
goto fail;
|
|
gpio -= chip->base;
|
|
if (gpio >= chip->ngpio)
|
|
goto fail;
|
|
status = gpio_ensure_requested(desc, gpio);
|
|
if (status < 0)
|
|
goto fail;
|
|
|
|
/* now we know the gpio is valid and chip won't vanish */
|
|
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
might_sleep_if(chip->can_sleep);
|
|
|
|
if (status) {
|
|
status = chip->request(chip, gpio);
|
|
if (status < 0) {
|
|
pr_debug("GPIO-%d: chip request fail, %d\n",
|
|
chip->base + gpio, status);
|
|
/* and it's not available to anyone else ...
|
|
* gpio_request() is the fully clean solution.
|
|
*/
|
|
goto lose;
|
|
}
|
|
}
|
|
|
|
status = chip->direction_input(chip, gpio);
|
|
if (status == 0)
|
|
clear_bit(FLAG_IS_OUT, &desc->flags);
|
|
|
|
trace_gpio_direction(chip->base + gpio, 1, status);
|
|
lose:
|
|
return status;
|
|
fail:
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
if (status)
|
|
pr_debug("%s: gpio-%d status %d\n",
|
|
__func__, gpio, status);
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_direction_input);
|
|
|
|
int gpio_direction_output(unsigned gpio, int value)
|
|
{
|
|
unsigned long flags;
|
|
struct gpio_chip *chip;
|
|
struct gpio_desc *desc = &gpio_desc[gpio];
|
|
int status = -EINVAL;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto fail;
|
|
chip = desc->chip;
|
|
if (!chip || !chip->set || !chip->direction_output)
|
|
goto fail;
|
|
gpio -= chip->base;
|
|
if (gpio >= chip->ngpio)
|
|
goto fail;
|
|
status = gpio_ensure_requested(desc, gpio);
|
|
if (status < 0)
|
|
goto fail;
|
|
|
|
/* now we know the gpio is valid and chip won't vanish */
|
|
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
might_sleep_if(chip->can_sleep);
|
|
|
|
if (status) {
|
|
status = chip->request(chip, gpio);
|
|
if (status < 0) {
|
|
pr_debug("GPIO-%d: chip request fail, %d\n",
|
|
chip->base + gpio, status);
|
|
/* and it's not available to anyone else ...
|
|
* gpio_request() is the fully clean solution.
|
|
*/
|
|
goto lose;
|
|
}
|
|
}
|
|
|
|
status = chip->direction_output(chip, gpio, value);
|
|
if (status == 0)
|
|
set_bit(FLAG_IS_OUT, &desc->flags);
|
|
trace_gpio_value(chip->base + gpio, 0, value);
|
|
trace_gpio_direction(chip->base + gpio, 0, status);
|
|
lose:
|
|
return status;
|
|
fail:
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
if (status)
|
|
pr_debug("%s: gpio-%d status %d\n",
|
|
__func__, gpio, status);
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_direction_output);
|
|
|
|
/**
|
|
* gpio_set_debounce - sets @debounce time for a @gpio
|
|
* @gpio: the gpio to set debounce time
|
|
* @debounce: debounce time is microseconds
|
|
*/
|
|
int gpio_set_debounce(unsigned gpio, unsigned debounce)
|
|
{
|
|
unsigned long flags;
|
|
struct gpio_chip *chip;
|
|
struct gpio_desc *desc = &gpio_desc[gpio];
|
|
int status = -EINVAL;
|
|
|
|
spin_lock_irqsave(&gpio_lock, flags);
|
|
|
|
if (!gpio_is_valid(gpio))
|
|
goto fail;
|
|
chip = desc->chip;
|
|
if (!chip || !chip->set || !chip->set_debounce)
|
|
goto fail;
|
|
gpio -= chip->base;
|
|
if (gpio >= chip->ngpio)
|
|
goto fail;
|
|
status = gpio_ensure_requested(desc, gpio);
|
|
if (status < 0)
|
|
goto fail;
|
|
|
|
/* now we know the gpio is valid and chip won't vanish */
|
|
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
|
|
might_sleep_if(chip->can_sleep);
|
|
|
|
return chip->set_debounce(chip, gpio, debounce);
|
|
|
|
fail:
|
|
spin_unlock_irqrestore(&gpio_lock, flags);
|
|
if (status)
|
|
pr_debug("%s: gpio-%d status %d\n",
|
|
__func__, gpio, status);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_set_debounce);
|
|
|
|
/* I/O calls are only valid after configuration completed; the relevant
|
|
* "is this a valid GPIO" error checks should already have been done.
|
|
*
|
|
* "Get" operations are often inlinable as reading a pin value register,
|
|
* and masking the relevant bit in that register.
|
|
*
|
|
* When "set" operations are inlinable, they involve writing that mask to
|
|
* one register to set a low value, or a different register to set it high.
|
|
* Otherwise locking is needed, so there may be little value to inlining.
|
|
*
|
|
*------------------------------------------------------------------------
|
|
*
|
|
* IMPORTANT!!! The hot paths -- get/set value -- assume that callers
|
|
* have requested the GPIO. That can include implicit requesting by
|
|
* a direction setting call. Marking a gpio as requested locks its chip
|
|
* in memory, guaranteeing that these table lookups need no more locking
|
|
* and that gpiochip_remove() will fail.
|
|
*
|
|
* REVISIT when debugging, consider adding some instrumentation to ensure
|
|
* that the GPIO was actually requested.
|
|
*/
|
|
|
|
/**
|
|
* __gpio_get_value() - return a gpio's value
|
|
* @gpio: gpio whose value will be returned
|
|
* Context: any
|
|
*
|
|
* This is used directly or indirectly to implement gpio_get_value().
|
|
* It returns the zero or nonzero value provided by the associated
|
|
* gpio_chip.get() method; or zero if no such method is provided.
|
|
*/
|
|
int __gpio_get_value(unsigned gpio)
|
|
{
|
|
struct gpio_chip *chip;
|
|
int value;
|
|
|
|
chip = gpio_to_chip(gpio);
|
|
WARN_ON(chip->can_sleep);
|
|
value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
|
|
trace_gpio_value(gpio, 1, value);
|
|
return value;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__gpio_get_value);
|
|
|
|
/**
|
|
* __gpio_set_value() - assign a gpio's value
|
|
* @gpio: gpio whose value will be assigned
|
|
* @value: value to assign
|
|
* Context: any
|
|
*
|
|
* This is used directly or indirectly to implement gpio_set_value().
|
|
* It invokes the associated gpio_chip.set() method.
|
|
*/
|
|
void __gpio_set_value(unsigned gpio, int value)
|
|
{
|
|
struct gpio_chip *chip;
|
|
|
|
chip = gpio_to_chip(gpio);
|
|
WARN_ON(chip->can_sleep);
|
|
trace_gpio_value(gpio, 0, value);
|
|
chip->set(chip, gpio - chip->base, value);
|
|
}
|
|
EXPORT_SYMBOL_GPL(__gpio_set_value);
|
|
|
|
/**
|
|
* __gpio_cansleep() - report whether gpio value access will sleep
|
|
* @gpio: gpio in question
|
|
* Context: any
|
|
*
|
|
* This is used directly or indirectly to implement gpio_cansleep(). It
|
|
* returns nonzero if access reading or writing the GPIO value can sleep.
|
|
*/
|
|
int __gpio_cansleep(unsigned gpio)
|
|
{
|
|
struct gpio_chip *chip;
|
|
|
|
/* only call this on GPIOs that are valid! */
|
|
chip = gpio_to_chip(gpio);
|
|
|
|
return chip->can_sleep;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__gpio_cansleep);
|
|
|
|
/**
|
|
* __gpio_to_irq() - return the IRQ corresponding to a GPIO
|
|
* @gpio: gpio whose IRQ will be returned (already requested)
|
|
* Context: any
|
|
*
|
|
* This is used directly or indirectly to implement gpio_to_irq().
|
|
* It returns the number of the IRQ signaled by this (input) GPIO,
|
|
* or a negative errno.
|
|
*/
|
|
int __gpio_to_irq(unsigned gpio)
|
|
{
|
|
struct gpio_chip *chip;
|
|
|
|
chip = gpio_to_chip(gpio);
|
|
return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__gpio_to_irq);
|
|
|
|
|
|
|
|
/* There's no value in making it easy to inline GPIO calls that may sleep.
|
|
* Common examples include ones connected to I2C or SPI chips.
|
|
*/
|
|
|
|
int gpio_get_value_cansleep(unsigned gpio)
|
|
{
|
|
struct gpio_chip *chip;
|
|
int value;
|
|
|
|
might_sleep_if(extra_checks);
|
|
chip = gpio_to_chip(gpio);
|
|
value = chip->get ? chip->get(chip, gpio - chip->base) : 0;
|
|
trace_gpio_value(gpio, 1, value);
|
|
return value;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
|
|
|
|
void gpio_set_value_cansleep(unsigned gpio, int value)
|
|
{
|
|
struct gpio_chip *chip;
|
|
|
|
might_sleep_if(extra_checks);
|
|
chip = gpio_to_chip(gpio);
|
|
trace_gpio_value(gpio, 0, value);
|
|
chip->set(chip, gpio - chip->base, value);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
|
|
|
|
|
|
#ifdef CONFIG_DEBUG_FS
|
|
|
|
static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
|
|
{
|
|
unsigned i;
|
|
unsigned gpio = chip->base;
|
|
struct gpio_desc *gdesc = &gpio_desc[gpio];
|
|
int is_out;
|
|
|
|
for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
|
|
if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
|
|
continue;
|
|
|
|
is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
|
|
seq_printf(s, " gpio-%-3d (%-20.20s) %s %s",
|
|
gpio, gdesc->label,
|
|
is_out ? "out" : "in ",
|
|
chip->get
|
|
? (chip->get(chip, i) ? "hi" : "lo")
|
|
: "? ");
|
|
seq_printf(s, "\n");
|
|
}
|
|
}
|
|
|
|
static int gpiolib_show(struct seq_file *s, void *unused)
|
|
{
|
|
struct gpio_chip *chip = NULL;
|
|
unsigned gpio;
|
|
int started = 0;
|
|
|
|
/* REVISIT this isn't locked against gpio_chip removal ... */
|
|
|
|
for (gpio = 0; gpio_is_valid(gpio); gpio++) {
|
|
struct device *dev;
|
|
|
|
if (chip == gpio_desc[gpio].chip)
|
|
continue;
|
|
chip = gpio_desc[gpio].chip;
|
|
if (!chip)
|
|
continue;
|
|
|
|
seq_printf(s, "%sGPIOs %d-%d",
|
|
started ? "\n" : "",
|
|
chip->base, chip->base + chip->ngpio - 1);
|
|
dev = chip->dev;
|
|
if (dev)
|
|
seq_printf(s, ", %s/%s",
|
|
dev->bus ? dev->bus->name : "no-bus",
|
|
dev_name(dev));
|
|
if (chip->label)
|
|
seq_printf(s, ", %s", chip->label);
|
|
if (chip->can_sleep)
|
|
seq_printf(s, ", can sleep");
|
|
seq_printf(s, ":\n");
|
|
|
|
started = 1;
|
|
if (chip->dbg_show)
|
|
chip->dbg_show(s, chip);
|
|
else
|
|
gpiolib_dbg_show(s, chip);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int gpiolib_open(struct inode *inode, struct file *file)
|
|
{
|
|
return single_open(file, gpiolib_show, NULL);
|
|
}
|
|
|
|
static const struct file_operations gpiolib_operations = {
|
|
.open = gpiolib_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = single_release,
|
|
};
|
|
|
|
static int __init gpiolib_debugfs_init(void)
|
|
{
|
|
/* /sys/kernel/debug/gpio */
|
|
(void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
|
|
NULL, NULL, &gpiolib_operations);
|
|
return 0;
|
|
}
|
|
subsys_initcall(gpiolib_debugfs_init);
|
|
|
|
#endif /* DEBUG_FS */
|